Is L1 or L2 Distance Metric More Sensitive to Outliers?

Learn why L2 (Euclidean) distance is more sensitive to outliers than L1 (Manhattan) distance and how this impacts data analysis.

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L2 (or Euclidean distance) is more sensitive to outliers compared to L1 (or Manhattan distance). This sensitivity arises because L2 squares the deviation, which amplifies the effect of larger differences. In contrast, L1 sums the absolute values of the deviations, making it more robust to outliers.

FAQs & Answers

  1. What makes L2 distance more sensitive to outliers than L1? L2 distance squares the deviations, which disproportionately increases the influence of larger differences or outliers, while L1 sums absolute deviations, reducing sensitivity to extreme values.
  2. When should I use L1 distance over L2 in data analysis? Use L1 distance when you want your analysis or model to be robust against outliers, as it is less affected by extreme values compared to L2.
  3. How do L1 and L2 distances differ mathematically? L1 distance sums the absolute differences between points, while L2 calculates the square root of the sum of squared differences, emphasizing larger deviations more.